1. Field of the Invention
The present disclosure relates generally to shock absorbers having secondary dampening assemblies. Specifically, the present disclosure describes secondary dampening assemblies, such as lockout pistons and lockout collars, hydraulic stop pistons and hydraulic stop sleeves, flow discs and orifice plugs, and dual-spring stops.
2. Description of the Related Art
Conventional shock absorbers known in the related art typically include an outer tube, a piston assembly, a rod, fluid, and one or more valves, whereby the piston assembly is connected to the rod and travels within fluid in the outer tube in operation so as to dampen axial movement of the rod with respect to the outer tube. To that end, respective opposing ends of the rod and outer tube are attached to different members or structures so as to dampen movement therebetween. By way of example, conventional automotive suspension systems utilize shock absorbers in connection with springs external to the shock absorber to control the suspension dampening in compression and rebound, whereby the shock absorber is typically attached to a knuckle supporting a wheel at one end, and to a portion of the vehicle's frame or body at the other end.
Depending on the application, the shock absorber may also include an inner tube disposed inside the outer tube, wherein the piston assembly is instead supported in the inner tube. The shock absorber is sealed at an end that receives the piston assembly. The inner tube defines a working chamber filled with fluid through which the piston assembly can move in operation. The piston assembly generally divides the working chamber into an upper working chamber and a lower working chamber. Similarly, a reservoir chamber is defined in the space between the outer tube and the inner tube. The reservoir chamber also contains fluid and is in regulated fluid communication with the working chamber via one or more valves. The chambers are sealed to prevent the leakage of fluid therefrom. The outer tube is typically manufactured from steel and, consequently, can be heavy. Since the outer tube is manufactured from steel, the end of the outer tube is sealed by known methods, such as crimping or roll forming. The outer tube typically engages a rod guide assembly to seal the chambers.
During normal shock absorber operation, the shock absorber is extended and compressed during vehicle wheel and body articulation. If the shock absorber is completely compressed during wheel or body articulation, a condition referred to as “bottoming out” occurs and causes an abrupt metal-to-metal noise. Further, the condition causes harsh feedback and/or vibrations that are felt by the driver.